Gargoyle, this is the problem. I had hoped by now someone would have written in and pointed out the name of the piece. I am relying purely on memory, possibly from as long as 40 years ago. My father put this record on and said"Gregor( as I was known in those days) what is that the tune of?" And I said "Waltzing Matilda", as would anyone else who heard it. And he went on and referred to is as a familiar fact/hypothesis in musical circles that this piece must have influenced the composer of Waltzing Matilda. And the trouble is I dont listen to a lot of Mozart, and I've never heard (or heard of) this piece of music since. I would guess it was chamber music, a string quartet or a piano quintet, something of that nature. And Iam damn sure it was the chorus of WM it was like, not the verse.And I'm almost certain it was more like the Cowan than the McPherson version..
I fully appreciate that may have dreamed thewhole incident, which is why I'm hoping for corroboration.I did once dream that the tune"Immortal Invisible" was the original tune for the song "The Princess Royal" so I know these things can happen.